Early on in the Disney Channel kidsploitation opus High School Musical, the film's basketball-star protagonist tells a friend that he's considering trying out for the titular play, and the friend responds thusly: "The music in those shows isn't hip-hop or rock or anything essential to culture. It's, like, show music." By the end of the movie, of course, that friend is ecstatically chirping along with the rest of the cast. Show music conquers all.

Something eerily similar happened in the 2006 pop marketplace: The High School Musical soundtrack, full of earnest Europop approximations of show music, turned out to be the year's runaway bestseller, moving 3.5 million units without any significant support from mainstream press or radio. In its first week, though, it entered the Billboard charts at an inauspicious

143, taking weeks to pick up steam before entrenching itself in the Top 10 for most of the first half of the year. That's the mark of a rare beast: the legitimate cult success. Judging by the crowd at a New Jersey HSM concert last month, that cult consists entirely of eight-year-old girls and their parents, a cult with apparently enough buying power to launch the movie's cast of unknowns beyond any rocker or rapper who released an album in 2006.

The album didn't blow up because show music had suddenly become essential to culture. Rather, its success mocked the very idea that anything could be essential to culture anymore. The music that sold the most in 2006 came from niche-market underdogs, not crossover monsters; the Starbucks-counter adult-contempo of James Blunt and the slickly inspirational Nashville country of Rascal Flatts easily outsold tabloid mainstays like Beyoncé. CD sales plummeted all year, and the only albums that held on were the ones targeted at those tiny slivers of the population who hadn't yet figured out how to download illegally.

Way back in 1984, Bruce Springsteen's Born in the U.S.A. narrowly won out over Prince's Purple Rain to top the P&J album chart. Both records were mass-culture events, transcending radio-format categorization and record-bin pigeonholing. In subsequent years, cult critical faves (Liz Phair, PJ Harvey, Lucinda Williams) have won out as often as chart monsters (Paul Simon, Nirvana, OutKast), but mass-culture totems have always found their place. In last year's poll, 21 critics voted for Mariah Carey's The Emancipation of Mimi, the biggest-selling album of 2005. The previous year, 32 critics placed Usher's chart-topping
Confessions on their ballots, good enough to vault it into the poll's Top 40. This year, though, High School Musicalgot one vote. That's not to say that we critics are out of touch with the massesvast swaths of the American public have never heard of
HSM. At least where music is concerned, there are no massesonly a series of stratified scenes with little or no overlap.

So then maybe today's definition of a major artist is one who manages to quietly cross the borders of those stratified scenes, slipping from one genre to another. One example would be Gnarls Barkley, who parlayed an intuitive sense for eye-grabbing gimmickry and an impeccable rap pedigree into play on urban and alt-rock and adult-contempo radio, and whose "Crazy" dominated our singles list in the process. And another, as always, is Timbaland, the maverick Virginia producer who's spent the past decade remaking the charts in his own image, approaching pop music with an auteur's sense of vision, and taking perverse delight in pulling ideas freely from anywhere he can imagine and piling them into staggering symphonies of rhythm. Most impressively, he's changed the sound of pop radio by forcing it to adjust to his own peculiarities, not by adjusting those peculiarities to fit pop radio. For Timbaland, there's no boundary between art and commerce; his most popular work also tends to be his most confounding and otherworldly.

Tim's output has dwindled slightly over the last couple of years, possibly because he's made the utterly bizarre decision to throw himself headlong into the world of competitive bodybuilding. He's largely distanced himself from onetime musical partner Missy Elliott, and he's moved away from the commercial rap that's been his primary outlet for years, only contributing the occasional track to a Diddy or a Young Jeezy record. But Timbaland may have had his most creatively and commercially successful year yet in 2006, taking whatever husks of mass-culture shared musical experience were left and molding them to fit his vision. If there was one inescapable non-"Crazy" song this year, it was Justin Timberlake's "My Love," a Timbaland track. Anyone randomly scanning radio stations this past December would encounter the song at least once, a truly impressive feat considering how weird the song is. Timberlake's voice flits elusively through wispy clouds of synthesizer and precariously piled-up layers of drums and mouth-clicks, eventually giving way to a loopy, punch-drunk rap verse from T.I. The lyrics are ridiculous, and there's no tune to speak of, but the track ebbs and crests and plummets with a spaced-out, dubby ecstasy. Timberlake's 2006 album FutureSex/LoveSounds is basically a full-length collaboration with Timbaland, and it's full of twisty, inventive soundscapes like this. In Timberlake, the producer found a partner willing to curl his own image all out of shape to better serve Timbaland's sonics, and the resulting album sold well without targeting any one audience. The union felt like a genuine pop event in a year conspicuously short on pop events.

Maybe it wasn't quite so momentous, but Timbaland also managed the near-impossible feat of turning the Canadian folk-pop warbler Nelly Furtado into a flirty electro ingénue with "Promiscuous" and "Maneater." It's almost unbelievable that Timbaland is just now digging deep into his bizarro-pop fantasies, 10 years after his name first rang bells. In a time when the star has all but gone extinct, the last pop auteur may be the big-money producer who gets weirder as he gets bigger. Maybe one day we'll even get to hear his take on show music.